The overall objective of this project is to characterize the biophysical properties of human lenses and elucidate some of the mechanisms involved in the development of lens fluorescence, pigmentation, aging and brown cataracts. We plan to continue with our studies on fluorescence in the lens (human, rat and rabbit) and on fluorescent peptides and fluorescent compounds derived from normal lenses and from brown 'nuclear' cataracts. Particular emphasis is placed on the use of non-destructive non-invasive spectroscopic methods (fluorescence, phosphorescence, adsorption, ESR, Raman and ODMR) for comparing and contrasting the properties of young and old normal lenses and cataractous lenses. We plan to correlate the results of these investigations with similar studies on specific proteins and fluorescent peptides derived from these lenses in order to compare the whole lens with the sum of its component structural proteins. Ambient ultraviolet radiation has been implicated as a significant factor in increased fluorescence and pigmentation as the lens ages and in the pathogenesis of nuclear sclerosis and the "brunescent cataract": We have proposed a model for lenticular aging based on exposing lenses (human and animal) to ultraviolet radiation. We hope to further elucidate and define specific mechanisms following UV exposure of lens proteins and correlate these findings with our observations on whole (UV irradated) lenses.